Scott, 30, whose 18 victories and 3.29 earned-run average were tops among Astros starters last year, could have filed for free agency after the 1986 season. Instead, he opted for a 3-year, $2.1 million contract earlier this month, a day before he was to go to arbitration.

''Now, I've got to prove last year wasn't a fluke,'' Scott said Saturday at spring-training camp at Osceola County Stadium.

A year ago, incentives increased Scott's $275,000 base salary to $350,000. Scott was asking $825,000 this season and rejected a $525,000 offer.

''Without a doubt, security was the biggest reason,'' Scott said.

A two-pitch -- fastball and slider -- pitcher, Scott knew he was in trouble when his slider quit working midway through the 1984 season. He lost all but one of his last eight decisions, finishing 5-11 with a 4.68 earned-run average.

''My slider, a pitch that had worked good for me for two years, suddenly was terrible,'' Scott said. ''I couldn't make it do anything. Instead of breaking, it was backing up and waiting to be hit. That left me a 92-mph fastball. Most pitchers can't survive throwing nothing but fastballs.''

Scott solicited San Francisco Manager Roger Craig's help to teach him the split-fingered fastball, or forkball.

''The forkball came to me very easily the first day I tried it,'' he said, estimating that it accounted for 40 percent of last year's pitches.

''I throw it just like a fastball, except that I hold the ball between my fingers. Changing how much space there is between the fingers makes the ball do different things. It has something to do with the size of your hands and fingers,'' Scott said, inspecting his long fingers.

Last spring Manager Bob Lillis instructed Scott to utilize the pitch as much as possible and not to be concerned if it took time to develop.

Midway through the Grapefruit League season, Scott pitched six perfect innings against St. Louis. ''That might have been the turning point,'' he said. ''I threw the forkball a lot. I didn't strike out many, but they weren't hitting the ball hard. It gave my confidence a big boost, and I kept pitching better and batter after that.''

The Chicago Cubs screamed the forkball was a little too good. After being beaten by Scott in Chicago, Manager Jim Frey accused Scott of doctoring the ball with sandpaper after Leon Durham reportedly found a scrap of sandpaper near the mound several days later.

''That was fun, a good laugh for a while,'' Scott said. ''Umps used to tell me they were going to be checking the balls, but they never threw one out of the game.''

Scott, a five-year major-league veteran, worked 221 2/3 innings last year, almost 68 more than his previous high with the Astros.

''I'd like to be a 20-game winner,'' said Scott, who had two no-decisions in his final three starts last year.